The continuous production of metallic anodes from molten metal has been described in U.S. Pat. Nos. 3,504,429 and 3,860,057, British Pat. No. 1,325,625 and German Offen. No. 2,250,792. In these continuous prior art processes, the metal strip is cut with a shear or a press. Unfortunately, none of these methods allows the direct manufacture of anodes shaped like those obtained by the slower, and therefore less economical conventional method of batch-wise casting in separate molds mounted on a casting wheel Anodes produced by the batch-wise technique have a prescribed thickness of some 40 to 50 mm and their shape is well known to those skilled in the art; in particular, their upper profile is characteristically designed to minimize the mass of that portion of the anode which is not immersed in the electrolytic refining bath, consistent with the structural stability of the anode. Anodes produced by batch-wise conventional methods are also flat enough to allow a minimum distance between electrodes in the electrolytic refining bath without risk of short-circuit. These three requirements (thickness, specific upper profile and flatness) cannot jointly be met by previously known continuous processes. On the one hand, the maximum thickness of anodes produced by known continuous processes is about 28 mm, when cut with shears, and only 15 mm when cut using a press. In addition, the shear cut method does not permit achievement of the above-mentioned upper profile without deforming the anode and thus impairing its flatness.
As a result of these drawbacks, prior continuous processes produce anodes with a high waste coefficient, (25 to 35%), said waste coefficient being the fraction, in percent by weight, of the anode that has to be remelted after electrolytic refining. These known processes also suffer the drawback in that a storage loop must be provided between the casting device and the cutting device. Within this storage loop, the cast metal is subjected to a rather strong bending stress, which very impure copper, such as copper with a high lead content, cannot withstand. The use of these known processes is thus limited to the production of anodes of relatively pure copper.
A need has therefore existed in the metallurgical art for a way of continuously producing metallic anodes from relatively impure molten metal and which satisfies the standard requirements of thickness, profile and flatness without engendering a high waste coefficient.
Accordingly, it is an object of the present invention to provide a process and apparatus for the continuous manufacture of metallic anodes from relatively impure metal, which anodes possess satisfactory thickness, profile and flatness with minimal waste of material.
Another object is to provide a process and apparatus as aforementioned which are adaptable to the use of very impure copper, e.g., blister and/or scrap copper.
These and other objects of the invention as well as a fuller understanding of the advantages thereof, can be had by reference to the following description, drawings and claims.